The Risks and Benefits of Taking Low-Dose Aspirin

Salicylic acid, the active ingredient in aspirin, has been used for thousands of years as an anti-inflammatory painkiller in the form of willow tree bark extract, which Hippocrates used to “treat fever and to alleviate pain during childbirth.” It became trademarked as a drug named Aspirin™ in 1899 and, to this day, “remains the most commonly used drug in the world.” One reason for its on-going popularity, despite the availability of better painkillers now, is that aspirin also acts as a blood thinner. Millions of people take aspirin on a daily basis to treat or prevent heart disease, which I explore in my video, Should We All Take Aspirin to Prevent Heart Disease?.

It all started in 1953 with the publication of the landmark study “Length of life and cause of death in rheumatoid arthritis” in the New England Journal of Medicine. The paper began with the sentence: “It has often been said that the way to live a long life is to acquire rheumatism.” The researchers found fewer deaths than expected from accidents, which could be explained by the fact that people with rheumatoid arthritis likely aren’t skiing or engaging in other potentially risky activity, but they also found significantly fewer deaths from heart attacks. Why would this be? Perhaps all the aspirin the subjects were taking for their joints was thinning their blood and preventing clots from forming in their coronary arteries in their heart. To find out, in the 1960s, there were calls to study whether aspirin would help those at risk for blood clots, and we got our wish in the 1970s: studies suggesting regular aspirin intake protects against heart attacks.

Today, the official recommendation is that low-dose aspirin is recommended for all patients with heart disease, but, in the general population (that is, for those without a known history of heart disease or stroke) daily aspirin is only recommended “when the potential cardiovascular [heart] disease benefit outweigh the risk of gastrointestinal bleeding.”

The bleeding complications associated with aspirin use may be considered an underestimated hazard in clinical medical practice. For those who have already had a heart attack, the risk-benefit analysis is clear. If we took 10,000 patients, daily low-dose aspirin use would be expected to prevent approximately 250 “major vascular events,” such as heart attacks, strokes, or, the most major event of all, death. However, that same aspirin “would be expected to cause approximately 40 major extracranial bleeding events,” meaning bleeding so severe you have to be hospitalized. Thus, the net benefit of aspirin for secondary prevention—for example, preventing your second heart attack—“would substantially exceed the bleeding hazard. For every 6 major vascular events prevented, approximately 1 major bleeding event would occur; therefore, the value of aspirin for secondary prevention is not disputed.”

If we instead took 10,000 patients who hadn’t ever had a heart attack or stroke and tried to use aspirin to prevent clots in the first place, that is, for so-called primary prevention, daily low-dose aspirin would only “be expected to prevent 7 major vascular events and cause 1 hemorrhagic stroke [bleeding within the brain] and 3 major extracranial bleeding events.” So, the benefits are approximately only 2 to 1, which is a little too close for comfort. This is why the new European guidelines do not recommend aspirin for the general population, especially given the additional risk of aspirin causing smaller bleeds within the brain as well.

If only there were a safe, simple solution free of side effects…and there is! Drs. Ornish and Esselstyn proved that even advanced, crippling heart disease could not only be prevented and treated, but also reversed, with a plant-based diet centered around grains, beans, vegetables, and fruits, with nuts and seeds treated as condiments, and without oils, dairy, or meat (including poultry and fish).

Long-time director of the longest-running epidemiological study in the world, the famous Framingham Heart Study, “Dr. William Castelli was asked what he would do to reverse the CAD [coronary artery disease] epidemic if he were omnipotent. His answer: ‘Have the public eat the diet of the rural Chinese as described by Dr. T. Colin Campbell…’” In other words, as he , “‘If Americans adopted a vegetarian diet, the whole thing would disappear,’ Castelli says of the heart disease epidemic.”

Dr. Esselstyn clarified that we’re not just talking about vegetarianism. “This new paradigm” of heart disease reversal means “exclusively plant-based nutrition.”


Did you know preventing heart disease and stroke aren’t the only benefits of an aspirin a day? A daily aspirin may also decrease the risk of certain cancers. In that case, should we take an aspirin a day after all? See Should We All Take Aspirin to Prevent Cancer? and Plants with Aspirin Aspirations.

For more on preventing, arresting, and reversing heart disease, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

How to Lower Your Sodium Intake

Reduction of salt consumption by just 15 percent could save the lives of millions. If we cut our salt intake by half a teaspoon a day, which is achievable simply by avoiding salty foods and not adding salt to our food, we might prevent 22 percent of stroke deaths and 16 percent of fatal heart attacks—potentially helping more than if we were able to successfully treat people with blood pressure pills. As I discuss in my video Salt of the Earth: Sodium and Plant-Based Diets, an intervention in our kitchens may be more powerful than interventions in our pharmacies. One little dietary tweak could help more than billions of dollars worth of drugs.

What would that mean in the United States? Tens of thousands of lives saved every year. On a public-health scale, this simple step “could be as beneficial as interventions aimed at smoking cessation, weight reduction, and the use of drug therapy for people with hypertension or hypercholesterolemia,” that is, giving people medications to lower blood pressure and cholesterol. And, that’s not even getting people down to the target. 

A study I profile in my video shows 3.8 grams per day as the recommended upper limit of salt intake for African-Americans, those with hypertension, and adults over 40. For all other adults the maximum is 5.8 daily grams, an upper limit that is exceeded by most Americans over the age of 3. Processed foods have so much added salt that even if we avoid the saltiest foods and don’t add our own salt, salt levels would go down yet still exceed the recommended upper limit. Even that change, however, might save up to nearly a hundred thousand American lives every year.

“Given that approximately 75% of dietary salt comes from processed foods, the individual approach is probably impractical.” So what is our best course of action? We need to get food companies to stop killing so many people. The good news is “several U.S. manufacturers are reducing the salt content of certain foods,” but the bad news is that “other manufacturers are increasing the salt levels in their products. For example, the addition of salt to poultry, meats, and fish appears to be occurring on a massive scale.”

The number-one source of sodium for kids and teens is pizza and, for adults over 51, bread. Between the ages of 20 and 50, however, the greatest contribution of sodium to the diet is not canned soups, pretzels, or potato chips, but chicken, due to all the salt and other additives that are injected into the meat.

This is one of the reasons that, in general, animal foods contain higher amounts of sodium than plant foods. Given the sources of sodium, complying with recommendations for salt reduction would in part “require large deviations from current eating behaviors.” More specifically, we’re talking about a sharp increase in vegetables, fruits, beans, and whole grains, and lower intakes of meats and refined grain products. Indeed, “[a]s might be expected, reducing the allowed amount of sodium led to a precipitous drop” in meat consumption for men and women of all ages. It’s no wonder why there’s so much industry pressure to confuse people about sodium.

The U.S. Dietary Guidelines recommend getting under 2,300 milligrams of sodium a day, while the American Heart Association recommends no more than 1,500 mg/day. How do vegetarians do compared with nonvegetarians? Well, nonvegetarians get nearly 3,500 mg/day, the equivalent of about a teaspoon and a half of table salt. Vegetarians did better, but, at around 3,000 mg/day, came in at double the American Heart Association limit.

In Europe, it looks like vegetarians do even better, slipping under the U.S. Dietary Guidelines’ 2,300 mg cut-off, but it appears the only dietary group that nails the American Heart Association recommendation are vegans—that is, those eating the most plant-based of diets.


This is part of my extended series on sodium, which includes:

If you’re already cutting out processed foods and still not reaching your blood pressure goals, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How to Increase Gut Bacterial Richness

We live in an “obesogenic environment,” with cheap junk food everywhere, thanks in part to subsidies going to the “‘food industrial complex,’ which manufactures obesogenic foods that foster addiction…The root causes…[may] make obesity difficult to escape,” but a lot of people do. If it were simply the external environment, why isn’t everyone obese?

“Some individuals seem to be more susceptible to the obesogenic environment…than others,” which suggests a genetic component, supported by studies of twins and adopted kids, but the genes that have been identified so far account for only 6 to 11 percent of the genetic variation in body mass index between individuals. Perhaps variation in our “other genome”—that is, all the different microbes that inhabit our body, known as the microbiome—may be playing a role. We have a hundred times more bacterial genes inside us than human genes.

As I discuss in my video Gut Microbiome: Strike It Rich with Whole Grains, a study found that people tend to fall into one of two groups: those who have lots of different types of bacteria in their gut (high “gut bacterial richness”) and those with relatively few types. Those with low bacterial richness had more overall body fat, insulin resistance, which is the cause of type 2 diabetes, high triglycerides, and higher levels of inflammatory markers, like C-reactive protein, compared to those with high bacterial richness. Not only did people with lower bacterial richness start out heavier, but the obese individuals with lower bacterial richness also gained more weight over time.

The question then becomes: Can a dietary intervention have any impact “A number of studies have associated increased microbial richness…with diets higher in fruits, vegetables, and fiber.”

Just giving fiber-type supplements doesn’t seem to boost richness, however, but the “compositional complexity” of a whole food, like whole grains, “could potentially support a wider scope of bacterial taxa,” types of bacteria, “thereby leading to an increase in diversity.” Human studies to investigate the effects of whole grains had been neglected, though…until now.

Subjects were given whole-grain barley, brown rice, or a mixture of both for a month, and all three caused an increase in bacterial community diversity. Therefore, it may take a broad range of substrates to increase bacterial diversity, and this can be achieved by eating whole plant foods.

Moreover, the alterations of gut bacteria in the study coincided with a drop in systemic inflammation in the body. We used to think that the way fiber in whole grains helped us was by gelling in our small intestine right off of our stomach, slowing the rate at which sugars were absorbed and blunting the spike in blood sugars one might get from refined carbs. We now know, however, that fiber is broken down in our colon by our friendly flora, which release all sorts of beneficial substances into our bloodstream that can have anti-inflammatory effects, as well. So, perhaps what’s happening in our large intestine helps explain the protective effects of whole grain foods against type 2 diabetes.

Interestingly, the combination of both barley and brown rice worked better than either grain alone, suggesting a synergistic effect. This may help explain “the discrepancy of the health effects of whole grains obtained in epidemiological [population-based] and interventional studies.”

Observational studies “strongly suggest” that those who consume three or more servings of whole grains a day tend to have a lower body mass index, less belly fat, and less tendency to gain weight, but recent clinical trials, where researchers randomized subjects to eat white bread rolls versus whole-wheat rolls, failed to provide evidence of a beneficial effect on body weight. Of course, whole grains are so superior nutritionally that they should continue to be encouraged. However, the “[i]nterventional trials might have failed to show [weight] benefits because they focused on a limited selection of whole grains, while in epidemiological trials [or the population studies], subjects are likely to consume a diverse set of whole grains which might have synergistic activities.”


Until recently, we knew very little about how powerfully our gut bacteria can affect our health. Catch up on the latest science with these related videos:

When it comes to rice, even white rice can be better than many choices, but brown rice is better and pigmented rice is probably the best. See my videos Kempner Rice Diet: Whipping Us Into Shape and Is It Worth Switching from White Rice to Brown? for more.

But what about the arsenic in rice? Learn more:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: